Wi-Fi is a wireless data communication and networking technology, specified by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards which define the physical layer (PHY) and medium access control (MAC) layer of the Open Systems Interconnection model (OSI Model).
Wi-Fi, and other non-3GPP standardised radio access technologies, provide radio coverage over relatively small areas, but at relatively high data rates. Such technologies are commonly referred to as Wireless Local Access Networks (WLAN). The use of unrestricted radio spectrum and relatively low-cost equipment for the provided data rates, has led to widespread deployment of WLAN access points. Access points may be private or public, with many commercial access points being positioned in public locations for use by customers. Access points may be managed and controlled by the cellular network providers/operators (“operator controlled access points”), or may be independent (“non-operator controlled access points”).
It is now common for mobile devices (UEs) be capable of establishing both cellular and WLAN connections. Where a UE has both a cellular and WLAN connection simultaneously it is common for the user to select which connection to use, and for the UE to route traffic accordingly. For example, when a UE connects to a user's home Wi-Fi network, the user's preferences set in the UE may indicate that all traffic should be routed by the UE via the Wi-Fi connection as opposed to the cellular connection.
3GPP LTE Release 12 introduced LTE/WLAN interworking to allow connection of a WLAN access points to an LTE core network, such that the WLAN access points act as a Radio Access Network (RAN) for the core network. Such an arrangement allows traffic to be routed via a WLAN, rather than the cellular RAN when the WLAN route is preferable. A UE connected to the cellular LTE RAN may measure signals received from WLAN access points and transmit those to the LTE RAN as options to provide services to the UE. The RAN may in turn report available access points to the core network, which may offload some or all traffic to that access point. The operator's core network is thus able to utilise either the operator's cellular network or WLAN network to serve their customers.
The 3GPP TS 24.312 LTE standard defines a core network entity known as the Access Network Discovery and Selection Function (ANDSF) which provides functions to assist UEs to discover non-cellular access networks, such as WLANs. UEs connecting to WLAN access points can transmit details of the access point (such as location and authentication details) to the ANDSF. Other UEs can then retrieve and utilise the information to discover and connect to the access point.
3GPP LTE Release 13 delegates more control to the LTE RAN to allow the LTE RAN to take decisions on the most appropriate RAN (LTE or Wi-Fi) for a UE. This functionality is known as LTE WLAN aggregation (LWA) as per 3GPP TS 36.300. However, user preferences specified at the UE should be taken into account by the LWA functionality. For example, a UE may be connected to an operator controlled access point and traffic may be routed to the UE using a combination of the LTE and WLAN access networks under the LWA procedures. If the UE comes within range of a non-operator controlled WLAN access point (WLAN-U), for which the user has specified a preference, for example their home Wi-Fi access point, LWA should respect that preference and all data should be sent via that non-operator controlled access point.
However, under the current systems, the RAN is not aware of user preferences for a WLAN-U and thus cannot terminate LWA to respect that preference.
It has been proposed that this situation be addressed by communicating preferences from the UE application layers (e.g. Connection Manager of Android OS) to the radio protocol layers for communication to the LTE RAN. These preferences can then be considered by the LWA function when deciding how to serve the UE. However, such behaviour requires modification of UE functionality and is therefore dependent on those UE operating system providers implementing the function.
It has also been proposed that WLAN access points transmit information on their UE connections to the LTE RAN. The LTE RAN can then consider this information in implementing LWA for a UE which is indicated as connected to a WLAN access point. However, this requires the providers of WLAN access points to modify their devices to make the required transmissions. It is unlikely that manufacturers and suppliers of non-operator controlled WLAN access points would make such modifications and therefore operation and widespread deployment cannot be assured.
There is therefore a requirement for a reliable means for LWA to account for user preferences specified at a UE.
The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known systems.